This invention pertains to timing mechanisms, and more particularly to timing mechanisms which utilize an eccentric drive to advance a cam means in a step-by-step manner.
Timing mechanisms of the type described herein have long been used in appliances such as dishwashers, washers, dryers, etc. to provide for sequential operation of the appliances according to a predetermined program. The predetermined programs are normally provided through a cam means, the cam means operating electrical switches to alternatively open and close circuits to operate the appliance functions. For the most part such cam means are advanced in a step-by-step manner through an intermittent drive means which in turn is driven by a constant speed drive means such as a synchronous motor.
Of recent years timing mechanisms have, because of the increasing amount of programming required, become increasingly complicated, especially the intermittent drive mechanism. One solution to this problem has been the use of coaxial drive systems wherein the drive means which intermittently engages and drives the cam means is driven by an eccentric. Such an arrangement, for the most part, simplifies the intermittent drive mechanism by reducing the number of elements required. And in addition such an arrangement permits the cam means to be advanced in varying degrees so as to use less cam space for "dead time" areas of a program. Typical of such arrangements are those described in U.S. Pat. No. 3,436,975 "Sequential Timer" issued Apr. 8, 1969; U.S. Pat. No. 3,053,947 "Sequential Timer" issued Sept. 11, 1962; and U.S. Pat. No. 3,683,711 "Sequential Timer" issued Aug. 15, 1972. While such arrangements have provided a suitable eccentric or coaxial drive, they are to a certain extent somewhat complicated.